Comment: I just read on tumblr a post that listed the last meals of
several prisoners who were executed. Victor Fueger who was the last to be
executed in Iowa to this day, asked for a single olive with the pit in it.
Some people have said that he was very allergic to olives, knew this, and
actually killed himself. Other websites claim that he was hanged as his
execution and that's how he died. What's the real story?

Only if his dead body was what was hung during his execution to cover up his suicide. And that adds a morbidity I can't imagine the original rumor-monger leaving out if such a thing was even speculated.